In electrical engineering, a resolver is an electromagnetic measuring transformer for converting the angular position of a rotor into an electrical quantity or into electrical signals. These signals are ultimately used to determine the relative angular position or the relative angular velocity between two assemblies which can rotate relative to each other, e.g., two machine parts rotatable in relation to each other. Resolvers also include measuring transformers, which are referred to as synchros or rotary resolvers.
Conventional resolvers are used for measuring an angular position between a stationary machine component (stator) and a machine component (rotor), which rotates relative to the stationary part.